tests: Add recursive associated type bound regression tests

tests/ui/traits/solver-cycles/129541-recursive-struct-and-array-impl.rs

@@ -0,0 +1,23 @@
+// Regression test for #129541
+
+//@ check-pass
+
+trait Bound {}
+trait Normalize {
+    type Assoc;
+}
+
+impl<T: Bound> Normalize for T {
+    type Assoc = T;
+}
+
+impl<T: Bound> Normalize for [T] {
+    type Assoc = T;
+}
+
+impl Bound for Hello {}
+struct Hello {
+    a: <[Hello] as Normalize>::Assoc,
+}
+
+fn main() {}